1. Technical Field Embodiments of the present disclosure are directed to processes for the manufacture of optical lens modules, particularly for use in devices or systems that employ multiple lenses.
2. Description of the Related Art
There are a number of devices that employ two or more lenses in a side-by-side arrangement. Examples of such devices include proximity sensors that use an emitter and a receiver positioned beside each other. The emitter produces a light signal, and when an object approaches the sensor, the signal is reflected by the object and detected by the receiver. Based on characteristics of the detected signal, such as, e.g., intensity, phase, focus, etc., proximity of the object can be determined.
Another example is found in many cell phone cameras, which have a camera lens positioned beside a flash lens.
Devices known as computational cameras employ multiple lenses in an array, each with a different filter to detect respective specific characteristics of a subject.
In each of the examples listed above, it is important that the lenses of the respective device have a specific positional relationship with each other. Generally, the lenses should have lens planes in common, or in some cases, the lens planes of the different lenses should a defined angle between their lens planes. It is therefore preferable to mount the lenses to a single structure so that their relative positions are precisely controlled. However, it is not usually advisable to form the lenses in a single piece of material. Two side-by-side sensor lenses should not, for example be ground from a single piece of glass, or molded into a single piece of optical plastic. Such a configuration can produce cross-talk, in which, for example, the signal generated by the emitter of a proximity sensor is reflected within the lens material and travels laterally, to exit from the other lens and prompt a false reading by the receiver. Thus, devices that employ multiple lenses typically include an opaque barrier between the lenses to prevent cross-talk.
In some cases, the individual lenses can be very small, on the order of, e.g., 1-4 mm in diameter, and positioned very close together, e.g., 500-1500 μm between lenses. Given the size and spacing of such lenses, manufacturing can present a challenge, and can be labor intensive. In one known process, holes are drilled into a small block of opaque material. The holes are filled with an optical plastic, and the block is then placed in a mold to form the faces of the lenses.